Grinder and elevator coupled through paddle wheel-equipped conduit



Dec. 23, 1969 L. G. REIMER GRINDER AND ELEVATOR COUPLED THROUGH PADDLEl WHEEL-EQUIPPED CONDUIT 4 l 2' IShee-tShSheet 1 Fil'ed Oct. 17. 1967 f mmm INVENTOR Leon G. Reimer BY 1j/ff WITNESSES @K/wlw.

TTO'RNEY Dec. 231969 L. G. REIMER 3,485,455 GRINDER AND ELEVATOR COUPLED THROUGH PADDLE WHEEL-EQUIPPED CONDUIT 'Y Filed Oct. 17, 1967 2 Sheets-Sheet 2y Patented Dec. 23, 1969 U.S. Cl. 241--186 8 Claims ABSTRACT OF THE DISCLOSURE There is disclosed a portion of a refuse treating system including a cylindrical grinder with a horizontally directed output in an upper quadrant of the grinder, the output being coupled through a transition conduit to the input of a continuous elevator, the conduit having within, a paddle wheel driven around a horizontal axis lying transversely of the conduit, the arr-angement is such that the paddle wheel and grinder rotor rotate in the same direction, and the ground refuse is ung by the grinder rotor elements at high speed through the conduit, most of the refuse passing over the top of the paddle wheel directly into the elevator input, while the balance falls out on and in the vicinity of the paddle wheel, which keeps the con duit from choking by throwing the fallout partly into the elevator input and partly back into the grinder.

Background of the invention In some refuse treatment systems, at a particular stage the refuse is ground in a grinder and the output of the grinder is fed to a bucket elevator for transmission to an upper level for further treatment. The material discharged from the grinder is quite heterogeneous with respect to particle size and physical characteristics, and also contains entrapped -air as well as refuse. The discharge velocity approaches the tip speed of the grinder rotating elements, and turbulence present in the materials discharged by the grinder has, in the past, defined the placement of the elevator. The slope ofthe discharge chute between the grinder and the elevator had to be quite steep to allow the ground material to tiow fast enough to prevent choking of the chute and to keep up with the movement of the elevator. The grinder, being the heavy piece of equipment, is properly located at ground level, and of necessity, in order to achieve the required slope, the elevator is located in a pit. The pit arrangement entails a high initial cost and also suffers from the disadvantage of day to day operating and maintenance problems caused by nuis-ance factors associated with the below ground-level pits.

Summary of the invention In accordance with one embodiment of the invention,

the grinder output is located at an upper quadrant of the grinder, and is coupled to the elevator input through a conduit in which a paddle wheel is rotated around an axis lying transversely ofthe conduit and in the same rotational direction as the grinder rotor. The arrangement is such that a major portion of the ground material is projected from the grinder output over the top of the paddle wheel directly to the elevator inlet, while fallout occurs on and adjacent to the paddle wheel whose operation prevents the throat of the conduit from choking by flinging material fall-out toward the elevator inlet and also by pushing material fall-out tow-ard and back into the grinder. The arrangement allows the boot of the elevator to -be at ground level, thus eliminating the pit arrangement and all its disadvantages.

It is therefore yan object of the invention to provide a novel coupling arrangement between the output of a rotary material grinder and the input of an elevator.

Another object is to provide an arrangement for transmitting the output of a rotary grinder to the boot of an elevator, which arrangement permits both grinder and elevator boot to be based at ground level.

A further object of the invention is a coupling arrangement between the output of a rotary grinder and the input of an elevator which eliminates the need of a belowground level elevator pit.

Other and further objects and advantages of the present invention will become apparent from the following detailed description taken in connection with the drawings wherein a preferred embodiment of the invention is illustrated.

In the drawings:

FIGURE 1 is a side elevation (partly broken awaypartly vertically sectioned) of an arrangement of a grinder coupled to an elevator in accordance with one embodiment of the invention;

FIG. 2 is a plan view of the apparatus shown in FIG. l, partly in horizontal section; and

FIG. 3 is a modied isometric view of the transition conduit between the grinder and elevator of FIG. 1, but without the internal paddle wheel.

Description of the preferred embodiment The apparatus in FIG. 1 includes a rotary grinder 10 having an outlet 12 coupled through a conduit or chute 14 to the inlet 16 of an elevator 18. The elevator is of any suitable type for instance a continuous type such as a screw type or an endless belt bucket type. A bucket type is shown by way of example. The upper or discharge end of the elevator is not shown, since an illustration thereof is not essential to an understanding of the invention.

The grinder 10, .shown by way of example as a chainharnmer type, is provided with a generally cylindrical housing 22 with closed ends defining a cylindrical grinding chamber 24. Opposite ends of the housing 22 are xed to end supports 26A, 26B, 26A and 26B secured to a base 28 which may be made of one or two tiers of I-beam networks to provide solidity and strength necessary for the support of the heavy grinder. Supports 26A and 26B are counterparts of supports 26A and 26B', respectively. The counterpart of an additional end support 27 is not visible in the drawings.

Disposed within the grinding chamber 24 is la rotor assembly 30y having a plurality of chain-harnmers 32 attached to a hub 34 that is fixed to a shaft 36 whose ends extend through small openings in opposite ends of the housing 22 and are journaled in bearings 38A and 38B carried by the end supports 26. In order to promote positive axial movement of the refuse in the grinder from the inlet toward the outlet, the chain-hammers 32 are preferably disposed around the grinder shaft 36 in a spiral pattern extending from one to the other end of the charnber, thereby providing a screw effect. Only two of the many chain-hammers 32 attached to the hub 34 are shown in FIG. 1 to avoid complicating the drawing. Further details of this type of rotor structure may be similar to that shown in U.S. Patent No. 2,965,320, which also shows cooperating stripper bolts that pass radially into the housing. Such stripper bolts or other stripping devices, although not shown herein, may be included in the grinder 10. The rotor 30 is driven counterclockwise, as viewed in FIG. 1, by a suitable motor 40 (FIG. 2) coupled to the rotor shaft 36 and mounted on the base 28.

At one end (FIG. 2) and in quadrant II (FIG. l), the housing 22 is provided with an inlet 42 having an upwardly facing rectangular opening 41 with an encircling flange or collar 44 for coupling the inlet to a conduit or chute for the receipt of incoming material to be ground in the grinder.

The grinder outlet 12 is at the opposite end (FIG. 2) and in quadrant II (FIG. 1) of housing 22. The outlet opening is rectangular and in a vertical plane facing the elevator and is encircled by a coupling ange 48 mated through an intervening resilient spacer 49 to a complementary coupling flange 50 around the inlet end (right end) of conduit 14. The resilient spacer 49, which may be made of rubber, minimizes transmission of vibration from the grinder to the conduit. The top of conduit 14 and the top of outlet 12 lie along a horizontal line that is tangent to the periphery of the cylindrical chamber 24. The input end of conduit 14 and the opening of grinder outlet 12 have corresponding rectangular shapes to provide a matching relation for the joinder of the conduit and the grinder outlet.

The conduit 14 is comprised of a rectangular fiat top section 52 lying in the horizontal plane, a rectangular flat bottom section 54 sloping downward from the grinder outlet toward the elevator, and a pair of spaced apart trapezoidal sidewalls 56A and 56B joining the top and bottom sections 52 and 54 to form a horn-shaped conduit. The small end (right end) of the conduit is matched with and coupled to the grinder outlet 12, while the wide end (output end) of the conduit is matched and coupled to the inlet 16 of the elevator. The elevator inlet 16 and the wide end of the conduit 14 have each a rectangular opening, both openings corresponding in size. The wide end of conduit 14 is provided with an encircling flange S8 to mate with the encircling edges of the elevator inlet 16. Suitable fastening means such as bolts, rivets, welding, etc. may be employed to join the flange 58 to the edges of the inlet 16 in order to provide a substantially dusttight joint. Fora better view of its structure, conduit 14 is shown out of context in FIG. 3. The top plate 52, may be permanently fixed to the side plates 56A and 56B, or it may be hinged at 59-59 to side plates 56A to provide a door for inspection and maintenance. The door 52 is shown closed in FIG. 1 and open in FIG. 3. The door may be fastened in the closed position by means of bolts 60 which screw into threaded holes 61 (FIG. 3).

Mounted within the conduit 14 is a paddle wheel 62 fixed to a horizontal shaft 64 extending transversely of the conduit and mounted for rotation in bearings 66A Iand 66B respectively fixed to the sidewalls 56A and 56B. The center line of shaft 64 must be vertically closer to the bottom portion 54 than to the top portion 52. In FIG. 3, the paddle wheel was omitted to provide a clearer picture of the conduit. The paddle wheel includes a plurality of blades 68 secured to and extending radially from a hub 70 that is fixed to the shaft 64. Large brass spacer washers 71 and 72 on the shaft at opposite ends of the hub 70 provide lateral bearing surfaces plus a seal against the ground material. By way of example, the blades 68 are shown as -liat rectangular paddles whose faces are parallel to the axis of shaft 64. The paddle wheel 62 is driven in the same direction as the grinder rotor 30` by any suitable means, for example by a motor 73 through reducing gears 74 coupled to the shaft 64 as diagrammatically illustrated in FIG. 2. Thus as viewed in FIG. 1, both the paddle wheel and the grinder rotor are driven counterclockwise.

The elevator assembly 18 includes a vertical tubular shaft 76 having a rectangular cross section and a boot portion 77 based at ground level. More specifically the shaft 76 comprises front wall 78, a back wall 80 parallel to and spaced to the rear of the front wall, and spaced parallel side walls 82 and 84. The arrangement of the front, back and side walls, provides a tubular shaft having a rectangular cross section, in other words a rectangular tube.

Within the shaft 76 is a motor-driven bucket elevator 86 shown sketchily in more or less diagrammatic form since mechanical and constructional details of such an elevator are well known in the art, 4and illustration of such details is unnecessary to an understanding of the invention. In general it may be seen that the bucket elevator 86includes a plurality of buckets 88 carried by an endless flexible belt 90 looped around a pulley 92 at the lower end, and around a motor-driven pulley (not shown) at its upper end. The upper pulley is driven to provide the movement of the buckets in the direction of the arrow 94 at an appropriate speed to provide centrifugal discharge and compatibility with the speed of the intake of ground materials from the grinder 22. A boot plate 95 across the bottom of the elevator keeps material from piling up in the lower corners of the elevator.

As seen in FIG. 1, the elevator inlet 16 is in the front wall 78 of the elevator shaft. This inlet is a rectangular opening which registers with the rectangular opening at the output end of conduit 14. As hereinbefore mentioned, the conduit 14 is provided at its output end with an encircling flange 58 for coupling that end of the conduit to the elevator shaft wall 84 with the opening of the conduit in registry with the inlet to the elevator. Any suitable fastening means such as bolts and gasketing may be employed to fasten fiange 58 intimately to the wall 84 to provide a dust-tight joint between the conduit 14 and elevator shaft 76.

In order to provide a fair idea of the dimensional order of this type of apparatus, certain dimensions and parameters of an operating example of the apparatus illustrated in the drawings are as follows: The diameter of the cylindrical chamber of the grinder is about 60 inches. The length of the grinder chamber is about y inches. The grinder inlet 42 has a rectangular opening about 30 x 37 inches. The rectangular opening of the grinder outlet 12 which matches the inlet end of conduit 14 is about 15 x 30 inches. The inlet opening 16 to the elevator shaft 76 matches the rectangular opening at the output end of conduit 14 and is approximately 15 x 34 inches. The shaft walls 78 and 80 are each about 24 inches wide, while the shaft walls 82 and 84 are about 60 inches wide. The pulley 92 is about 24 inches in diameter. The bucket elevator is driven at a lineal speed of about 38() r.p.m. The paddle wheel 62 is driven at about 90 r.p.m. The grinder rotor 30 is driven at about 670 r.p.m. so that material projected from the grinder through its outlet 12 and into conduit 14 is substantially at the tip speed of the chainhammers which is about l2() m.p.h. The above-axis (above the rotational axis) horizontal tangential velocity of any point on substantially the outer radial half (portion from mid-point of radius to outer end of radius) of the chain-hammers is on a horizontal line passing between the top 52 of the conduit 14 and the top of the paddle wheel 62. The top of the paddle wheel is the radial outward extremity of a paddle when directly above the paddle wheel axis. The apparatus in the drawing is shown on a reduced scale from a full-size example with relative proportions substantially maintained.

The arrangement and relations are such that a major portion, for example more than 50%, of the material discharged from the grinder outlet 12 passes over the top of the paddle wheel 62. Thus more than 50% of the discharged material enters the elevator inlet 16 directly, that is, on the iiy, while the `balance of the discharged material falls out on the paddle wheel and on the bottom 54 of the conduit 14 in the vicinity of the paddle wheel. The fall-out is due to different material weights and to turbulence occurring in the throat of the conduit and generated by complicated air fiow patterns and mechanical reections such as carom, ricochet, etc. Although the slope of the conduit bottom 54 is such that the material fall-out moves downward (by gravity) and into the elevator input inlet 16, the slope is not sufiicient to move the material fast enough to keep the conduit from choking without the help of the paddle wheel 62. The

paddle wheel keeps the throat of the conduit from choking up by flinging part of the fall-out material into the elevator inlet and by a 'combination of flinging and nudging parts of the fall-out material back into the grinder chamber 24. Some of the paths of material discharged from the grinder are indicated by the shower 96 of singleheaded arrows. Some of the material paths generated by the paddle wheel are indicated by the doubleheaded arrows. From the above it is seen that the main stream of the material discharged from the grinder outlet is over the top of the paddle wheel.

In order to allow more than 50% of the discharged material to be flung directly from the`grinder into the elevator inlet over the top of the paddle wheel it is pre- -ferred that the relations f the conduit and paddle wheel be such that of the area of a vertical cross-section of the conduit at the axis of the paddle wheel, the part which lies above a line lying along the top of the paddle wheel and transversely of the conduit is at least of the order of 50% of the total area of ,said cross-section. In other words, the area defined by X times Z (FIGS. 1 and 2) is at least of the order of 50% of the area defined by (X -i- Y) tim-es Z, where X is the'fdistance between the top of the paddle wheel 62 and the top 52 of the conduit (FIG. 1), Y is the distance from the top of the paddle wheel to the bottom 54 of the-conduit (FIG. 1) along a vertical line passing through the paddle `wheel axis, and Z is the transverse or width dimension of the conduit (FIG. 2), that is Z is the distance between side walls 56A and 56B of the conduit.

Part of the material flung into the elevator through inlet 16 lands directly into the elevator buckets 88, while other parts strike the belt 90 as a backstop and ricochet or bounce into the buckets indirectly. Some of the material will drop to the boot plate 95 from which it is scooped up by the passing buckets88.

It is important that the paddle wheel keep the bottom of the conduit 14 clean in the area of the grinder discharge, and therefore the speed of the paddle wheel must be chosen to handle the volume of material which ltends to fall out of the grinder discharge. In the operating example having the approximate dimensions and speeds hereinbefore given, the grinder discharges a volume of 50 c.f.m. and the fall-out approaches 25% or 121/2 c.f.m., the balance of 75% or so being fl'png from the grinder outlet on the fly over the paddle wheel and into the elevator inlet. The volumetric clean out capacity of the paddle wheel feeder is two cubic feet per revolution, and if the maximum efficiency is approximately 17%, a speed of 37 r.p.m. for the paddle vwheel is the minimum requirement. Another consideration that must be met is the average linear speed of the paddle to effectively deliver the material to the elevator. An average speed of 300 f.p.m. is deemed desirable. If the midpoint of the paddle circumference is 3.14 feet per revolution, a speed of 96 r.p.m. is required to transfer the material to the elevator. The particular exemplary `installation referred to hereln operates at 92 r.p.m. thus closely approximating the 96 r.p.m. speed required to transfer the material to the elevator and more than enough to satisfy the 37 r.p.m. speed requirement to satisfy volunletric requirements.

Following are some relations which are critical to realizing the greatest efficiency from the invention. Conduit bottom 54 slopes downward in a direction from the grinder toward the elevator. The top 52 of the conduit is preferably horizontal, or if not horizontal, then sloping upward from the grinder in the direction of the elevator. The lower edge of the grinder outlet opening preferably is not below the grinder shaft. The paddle wheel shaft is preferably higher than the grinder rotor shaft.

It is to be understood that the hereindescribed arrangements are simply illustrative of the principles of the invention, and that other embodiments and applications are within the spirit and scope of the invention.

I claim as my invention:

1. In a refuse treatment system,

(A) a refuse grinder having (a) housing means defining a grinding chamber with an outlet having upper and lower edges, and

(b) refuse contacting element means within the chamber and rotatable about a first axis for reducing the refuse, said outlet being so arranged that when rotation of said refuse contacting element means is in a particular direction refuse in the grinder impelled by said element means will be flung through said outlet,

(B) elevator means laterally spaced from said grinder and having an inlet with upper andl lower edges, the lower edge of said inlet being lower than the lower edge of said outlet,

(C) a feeder conduit connecting said outlet to sa1d inlet, said conduit having (a) a top portion extending between the upper edge of said inlet and the upper edge of said outlet,

(b) a bottom portion sloping downward from the lower edge of said outlet to the lower edge of said inlet, and

(c) a paddle wheel mounted for rotation within said conduit about a generally horizontal second axis extending transversely of the conduit, said second axis being vertically closer to the bottom portion of the conduit than to the top portion of the conduit,

(D) first driving means for driving said refuse contacting element means in said particular direction, and

(E) second driving means for driving the paddle wheel in the same rotational direction as that of said refuse contacting element means.

2. The combination as in claim 1 wherein the rotational axes of the paddle wheel and the refuse contacting element means are substantially parallel and that of the paddle wheel is higher than that of the refuse contacting element means.

3. The combination as in claim 1 wherein the relations of the paddle wheel and said conduit are such that of the area of a vertical cross section of the conduit through the axis of the paddle wheel, the part which lies above a line lying along the top of the paddle wheel and transversely of the conduit is at least of the order of 50% 0f the total area of said cross section.

4. The combination of claim 1 wherein the rotational axis of the refuse contacting element means is substantially horizontal and the lower edge of said outlet is at least as high as that axis.

5. The combination as in claim 1 wherein the upper edge of said inlet is at least as high as the upper edge of said outlet.

6. The combination as in `claim 1 wherein:

(F) said chamber is a horizontal cylinder,

(G) said first axis is along the axis of the cylinder, an

(H) the arrangement of the conduit and grinder is such that a horizontal tangential velocity of said refuse contacting element means when rotating in said particular direction is along a line passing from the element means and between the top portion of the conduit and the top of the paddle wheel.

7. The combination as in claim 1 wherein:

(I) said chamber is a horizontal cylinder,

(J) said first axis is along the axis of the cylinder, and

(K) said outlet is in an upper quadrant of the cylinder and has its opening facing laterally toward said inlet.

8. The combination as in claim 1 wherein:

(L) said chamber is a horizontal cylinder,

(M) said first axis is along the axis of the cylinder, and

(N) the arrangement of the conduit and grinder is such that the above-axis horizontal tangential velocity of any point on substantially the outer radial half of 7 8 the refuse contacting element means is on a hori- ROBERT C. RIORDON, Primary Examiner zontal line passing between the top portion of the conduit and the top of the paddle Wheel. M' G RASKIN. Assi-stam Examiner References Cited 5 l U.S. CI.X.R. UNITED STATES PATENTS 241 9A7 v 'f 945,160 1/1910 GOetZ 241--186 X 2,230,195 1/1941 Warren. 

